Dr. Kevin Yip

Dr Kevin Yip
Orthopaedic Surgeon
MBBS(UK), FRCS(EDIN), FAM(SING), FHKCOS(ORTHO)

Featured on Channel NewsAsia

Cartilage

Key Points

  • Full-thickness articular cartilage defects have a limited capacity to heal. Thus, articular cartilage lesions and osteochondral defects in any joint present a challenging problem.
  • Cartilage lesions are less likely to be seen in the glenohumeral joint than in the knee, therefore there has not been extensive research on shoulder cartilage repair.
  • Making the diagnosis without the benefit of an arthroscopic visualization of the joint can be problematic.
  • Mechanical injuries include direct trauma to the cells and matrix, causing an acute disruption of the surface, or more subtle changes attributable to damage of the matrix macromolecules.
  • Biologic injuries include metabolic abnormalities, most commonly osteoarthritis, but also avascular necrosis and a variety of osteochondral injuries.
  • Although the use of gadolinium-enhanced arthrograms has improved diagnosis, a significant portion of lesions are not identified prospectively.
  • The goal of treatment is often to restore durable hyaline cartilage through a practical and minimally invasive approach (preferably arthroscopic), which is associated with minimal morbidity postoperatively and in the long term.
  • The end-stage management of many cartilage lesions is a replacement procedure. A titanium coated shaft portion with an articular bearing surface of cobalt-chrome alloy is implanted in the central articular defect and recreates the circumference of the humerus.
  • The goals of arthroscopic debridement are primarily to relieve pain and secondarily to improve function. The removal of loose tissues that cause pain and impingement helps to achieve these goals.
  • The decision making process for arthroscopic debridement is radiographic analysis. The proper views are critical to allow an appropriate diagnosis. These include an anteroposterior (AP) view in internal rotation, an AP view in the scapular plane with the arm in external rotation and slight abduction and an axillary view.

Articular cartilage lesions and osteochondral defects in any joint present a challenging problem to both patient and physician. The critical issue is that full-thickness articular cartilage defects have a limited capacity to heal at any age. Many procedures have been described to improve the joint alignment, induce reparative tissue proliferation or provide cartilage tissue that is more nearly normal.

The bulk of this work has occurred in lesions about the knee, with very little research in any other joints. The use of autogenous and allograft reconstruction of focal defects has been extensively studied in the knee. Other techniques including abrasion arthroplasty, drilling, and microfracture have been described for smaller lesions.

There is a paucity of research that discusses the problem of cartilage lesions about the glenohumeral joint and provides treatment recommendations, with the exception of a few case reports and small series of patients.

Certainly, the problem is less likely to be seen about the glenohumeral joint and therefore impacts the lack of need for extensive research. Complicating the problem is that unlike the knee, there is significant difficulty with access to the joint when a lesion is identified. Furthermore, the management options are not as obvious as a result of the lack of large-scale research.

There is a spectrum of pathology encountered with the lesions ranging from simple chondral delamination injuries to more extensive osteochondral injuries and culminating in arthritic degeneration of the glenohumeral joint. All of these lesions can be encountered in the typical active population commonly seen in the average sports medicine practice.

Making the diagnosis can also be problematic without the benefit of arthroscopic visualization of the joint. Several series point to the need for improved imaging techniques that allow better determination of the articular surfaces in a prospective fashion and this area also requires further study. In addition, the concurrent association of cartilage defects with the status of other areas of the joint, specifically, the rotator cuff and impingement is poorly understood both with respect to etiology and treatment.

After the diagnosis has been made, there are many options available for treatment if the management algorithms follow those historically applied to knee pathology. There are a variety of autogenous techniques including osteoarticular harvest with subsequent transplantation as well as the more complex technique of biologic regeneration of cartilage.

Allograft applications are also available and those include fresh and preserved specimens. In addition to the biologic resurfacing techniques, there are also devices that allow for resurfacing using metallic and other materials. Finally, in cases of limited damage or sometimes in the face of extensive degeneration of the cartilage surfaces, arthroscopic techniques can be employed primarily for symptom amelioration.

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